latitude-longitude | 易学教程

lat/lon conversion to x/y-coordinates

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问题 I have a openstreetmap image. left upper corner is lat: 80 lon: -169 and right lower corner is lat:-56 lon: 190 The image has the width: 2618 and the height: 1513 How do I convert given lat/lon-coordinates to the pictures x/y-coordinates? I tried it by myself, but couldn't figure out how to convert the coordinates. I hope someone can answer my question. 回答1: The question, as asked, is almost nonsensical. The area requested covers almost the entire globe, from 80N 169W to 56S 190E. That leaves

MySQL GeoSpatial function for ST_Distance_Spheroid? Metric used in return Type of GLength?

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Is there a ST_Distance_Sphere, ST_Distance_Spheroid equivalent function in MySQL's GeoSpatial Support? If not, any way to emulate this? What is the metric used in return type of GLength (length of the LineString)? The manual for GLength says that GLength() is a nonstandard name. It corresponds to the OpenGIS Length() function. But I couldn't find any Docs for OpenGIS Length(). All I found was for ST_Length are they the same? Also for accuracy do I need to specify the SRID(4326)? How Do I do this in MySQL? Since MySql 5.1 there are provided GIS functions distance_sphere() and distance_spheroid(

Pass Latitude/longitude via intent

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问题 I have collected different latitude and longitude of locations. I want to know if i can set them as string of array for e.g(String lat = {"9385853.0094", "23123123.234")and then pass them via intent so that i can display the location in google map using lat/long in new activity. 回答1: For example you have two classes called Maps.java and Routes.java. Use the following code to pass the LatLng LatLng fromPosition = new LatLng(9385853.0094, 23123123.234 ); LatLng toPosition = new LatLng(11

Print Longitude and Latitude in textbox Android

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问题 I have looked about and cannot find any direct threads regarding what I am looking for. I am trying to create an Android application which dials out an emergency number at the push of a button (which I have got working) but cannot get the location (displayed in Longitude and Latitude) to display, I have tried doing it with Toast and EditText boxes. I am new to Android development so wanted to start with something easy, but the LongLat part is being troublesome. Any help would be greatly

Geo circle to rectangle coordinates

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问题 Given the input, center latitude, center longitude and radius in kilometers, I want to get the coordinates for the rectangle that contains this circle (northeast and southwest lat/lng). Should I write the method myself? Even though I'm afraid not to account for some things as my math is rusty. Or can I find a ready implementation for java? I have google maps sdk in my project but I couldn't find anything useful there. 回答1: I suppose your square radius is much smaller than the earth's radius

to calculate driving distance between two coordinates on earth in php

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问题 Well i am working in a location based app and i need to find driving distance between two location on earth at the server end. i am coding the web service in php. Till now i am able to calculate the aerial distance using the Haversine formula, but now i want to calculate the driving distance. There can be possible duplicates for this question, but i was not able to find any help to calculate the "Driving distance" between two "coordinates" ie latitude and longitude instead of addresses in PHP

FQL query for finding public event

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问题 I would like to execute an FQL query for retrieving all the public events in a specific area (using longitude,latitude and maximum distance or simply location name). Do you know if it's possible? Apparently, somebody is able to do it, somehow: http://elmcity.info/fb_events?location=tokyo 回答1: It is possible indeed to receive events using location based "search" To do so you'll need the longitude and latitude coordinates of the location you want to search and a access_token with user_events

Find destination coordinates given starting coordinates, bearing, and distance

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问题 I'm looking at the formula listed here: http://www.movable-type.co.uk/scripts/latlong.html I seem to be having trouble as the resulting coordinates are not what I would expect them to be. Given the following information: Start lat: 28.455556 Start lon: -80.527778 Bearing: 317.662819(Degrees) Distance: 130.224835(Nautical miles) def getEndpoint(lat1,lon1,bearing,d): R = 6378.1 #Radius of the Earth brng = math.radians(bearing) #convert degrees to radians d = d*1.852 #convert nautical miles to

a failed attempt at placing a dot over an image based on known lat and lng points

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问题 I apologize for the vague title, I really can't figure out a batter way to sum it up. Suggestions are more than welcome. I'm working on a project that really doesn't NEED a google map, it'd just create extra overhead for this project. But, I can't figure out how to do this WITHOUT google maps... so far. If I were to place a graphical overlay of a floor plan into google maps, I could use a browser location to approximate a users position. For this, it's a VERY large place, so there's room for

Using a C function in Objective-C (for iPhone)

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问题 'lo all. I am a self-described admitted noob in iPhone programming (having a much longer perl & web background -- 30 years)...but took the plunge last week and bought a couple of good books. After cramming and reading well over 1000 pages -- and understanding it pretty well, I am well on my way to a good first Native iPhone app. My problem is this: I do not know how to do a simple Geographic (lat/long) point-in-polygon routine in Objective-C. I have 2 ways of doing this. One in C (the first